The present invention relates to systems for protecting the legitimacy of an article and in particular to systems for verifying the authenticity of an electronic document or article against forgery.
Verifying the authenticity of a document or article is a well-known problem that is made increasingly more difficult with the widespread use of sophisticated reproduction technologies. This is particularly the case in relation to digital media. Sophisticated reproduction systems are readily available. Even home computer systems are capable of performing reproduction functions that until not very long ago were only capable of being performed by large institutions, such as government agencies and large corporations, due to the resources that were required. Thus, technology capable of facilitating the counterfeiting or misuse of documents is widespread. Consequently, attempts have been made to provide methods and systems for verifying the authenticity of documents and articles such as identification cards against forgery or fraud.
U.S. Pat. No. 5,719,939 describes a system and method for verifying the legitimacy of a product against forgery. A pattern of overlying individual fibres is embedded in a transparent base material, so that the fibres form differing geometrical configurations. The fibres are capable of being optically scanned through a surface of the transparent base material. Subsequently, an inspector may scan the product and compare the obtained data with the stored data in an attempt to verify the authenticity of the product.
However, the security of the method disclosed in U.S. Pat. No. 5,719,939 is heavily dependent on the different geometrical configurations of the particular fibres. If the configurations are too simple, security cannot be guaranteed. On the other hand, if the configurations are too complex, the costs of the system increase significantly.
U.S. Pat. No. 5,742,685 discloses a method for verifying an identification card and recording a verification of the same. An image of a person whom the identification card is to identify is scanned to produce a digital signal associated with a text message. They are compressed, encrypted, and then coded as a two-dimensional barcode. The barcode is then printed on the back of the identification card. To verify the validity of the card, the barcode is scanned, decoded, decrypted, expanded and displayed. To perform verification, the resulting displayed image and text are compared with the corresponding information printed on the card.
While the method of U.S. Pat. No. 5,742,685 utilises a cryptographic connection between the printed image and the text on the one hand and the printed barcode on the other, there are several disadvantages of this method, relating to the practicability and complexity of the method. One such difficulty is how to compress an entire image to a size that satisfies the requirements of encryption and barcode encoding, while maintaining image quality. Significant compression can cause a significant degradation in the capacity to the recovered image with the original image. A further disadvantage is that a separate encryption/decryption key is required
There is therefore a need for an improved technique of verifying the authenticity of an article, especially an electronic document.
In accordance with a first aspect of the invention, a method of embedding linked watermarks in an article requiring protection against forgery is disclosed. The method includes the steps of: extracting information from a first portion of the article; encrypting the extracted information from the first portion; generating a watermark using the encrypted information; rendering the watermark to a second portion of the article; and repeating the extracting, encrypting, generating and rendering steps with another portion of the article until all relevant information of the article has been processed and a cryptographic link is formed thereby.
Preferably, the watermark is generated based on a selected watermark generating mechanism dependent upon the encrypted information. Further, each of the watermarks can be generated based on different watermark generation mechanism. Still more preferably, seeds for generating a watermark can be obtained from only one portion of the article or several selected portions of the article.
Preferably, the information is extracted directly from text and/or from one or more invariant features of an image. The image can depict biometric data of a person associated with the article.
Preferably, the article is an electronic document. It can also be a printed document.
In accordance with a second aspect of the invention, there is disclosed an apparatus for embedding linked watermarks in an article requiring protection against forgery. The apparatus includes: a device for extracting information from a first portion of the article; a device for encrypting the extracted information from the first portion; a device for generating a watermark using the encrypted information; a device for rendering the watermark to a second portion of the article; and a device for controlling repeated operation of the extracting, encrypting, generating and rendering devices with another portion of the article until all relevant information of the article has been processed and a cryptographic link is formed thereby.
In accordance with a third aspect of the invention, there is disclosed a computer program product having a computer readable medium having a computer program recorded therein for embedding linked watermarks in an article requiring protection against forgery, the computer program product including: a module for extracting information from a first portion of the article; a module for encrypting the extracted information from the first portion; a module for generating a watermark using the encrypted information; a module for rendering the watermark to a second portion of the article; and a module for controlling repeated operation of the extracting, encrypting, generating and rendering modules with another portion of the article until all relevant information of the article has been processed and a cryptographic link is formed thereby.
In accordance with a fourth aspect of the invention, there is disclosed an article requiring protection against forgery or fraud. The article includes: two or more portions for containing information, the information including text, biometric data, or both; two or more watermarks, each watermark printed in a respective one of the portions and being dependent upon information in a different portion, whereby a cryptographic link is formed between the two or more portions.
Preferably, the article is an electronic document. It can also be a printed document.
In accordance with a fifth aspect of the invention, there is disclosed an article requiring protection against forgery or fraud. The article is formed by the steps of: extracting information from a first portion of the article, the article having two or more portions for containing information, the information including text, biometric data, or both; encrypting the extracted information from the first portion; generating a watermark using the encrypted information; rendering the watermark to a second portion of the article; and repeating the extracting, encrypting, generating and rendering steps with another portion of the article until all relevant information of the article has been processed so that two or more watermarks are formed, each watermark being rendered in a respective one of the portions and being dependent upon information extracted from a different portion, whereby a cryptographic link is formed between the two or more portions.
In accordance with a sixth aspect of the invention, there is disclosed a method of forming an article requiring protection against forgery. The method includes the steps of: generating an invisible watermark dependent upon information contained in the article; and rendering the watermark within an official seal placed on the article, the official seal being a securely controlled item of an authority.
Preferably, the article is an electronic document. It can also be a printed document.
Preferably, the method includes the steps of: extracting information from a portion of the article; and encrypting the extracted information. The information can be extracted directly from text, or from one or more invariant features of an image. The image can depict biometric data of a person associated with the article.
In accordance with a seventh aspect of the invention, there is disclosed an apparatus for forming an article requiring protection against forgery. The apparatus includes: a device for generating an invisible watermark dependent upon information contained in the article; and a device for rendering the watermark within an official seal placed on the article, the official seal being a securely controlled item of an authority.
In accordance with an eighth aspect of the invention, there is disclosed a computer program product having a computer readable medium having a computer program recorded therein for forming an article requiring protection against forgery. The computer program product includes: a module for generating an invisible watermark dependent upon information contained in the article; and a module for rendering the watermark within an official seal placed on the article, the official seal being a securely controlled item of an authority.
In accordance with a ninth aspect of the invention, there is disclosed an article requiring protection against forgery or fraud. The article includes: a portion containing information, the information including text, biometric data, or both; an official seal placed on the article, the official seal being a securely controlled item of an authority; and an invisible watermark dependent upon the information and being rendered within the official seal.
Preferably, the article is an electronic document. It can also be a printed document.
In accordance with a tenth aspect of the invention, there is disclosed an article requiring protection against forgery or fraud. The article is formed by the steps of: generating an invisible watermark dependent upon information contained in the article, the information including text, biometric data, or both; and rendering the watermark within an official seal placed on the article, the official seal being a securely controlled item of an authority.
In accordance with an eleventh aspect of the invention, there is disclosed a method of verifying the legitimacy of an article against forgery. The method includes the steps of: inputting the article as two or more portions; extracting at least one watermark from each portion; determining a watermark from information in each portion; comparing the extracted watermark from one portion with the determined watermark from a different portion to determine if a corresponding cryptographic link is found; and repeating the comparing step until all portions of the article have been processed, the article being verified as a legitimate article if all cryptographic links are found between the two or more portions.
Preferably, the method includes the steps of: scanning the product; and dividing the scanned product into two or more portions. It can also include the step of scanning information from a portion of the product to reconstruct a seed to a generated watermark using a cryptographic technique carried out in a process of embedding a watermark in the portion. More preferably, the method includes the step of: extracting an invariant feature from the scanned information to reconstruct the seed. The extracted, invariant feature can include biometric data.
Preferably, the method also includes the step of decrypting the scanned information to reconstruct the seed. Optionally, a cryptographic link can be a self-circle, that is referring back to itself.
In accordance with a twelfth aspect of the invention, there is disclosed an apparatus for verifying the legitimacy of an article against forgery. The apparatus includes: a device for inputting the article as two or more portions; a device for extracting at least one watermark from each portion; a device for determining a watermark from information in each portion; a device for comparing the extracted watermark from one portion with the determined watermark from a different portion to determine if a corresponding cryptographic link is found; and a device for repeating the comparing step until all portions of the article have been processed, the article being verified as a legitimate article if all cryptographic links are found between the two or more portions.
In accordance with a thirteenth aspect of the invention, there is disclosed a computer program product having a computer readable medium having a computer program recorded therein for verifying the legitimacy of an article against forgery. The computer program product includes: a module for inputting the article as two or more portions; a module for extracting at least one watermark from each portion; a module for determining a watermark from information in each portion; a module for comparing the extracted watermark from one portion with the determined watermark from a different portion to determine if a corresponding cryptographic link is found; and a module for repeating the comparing step until all portions of the article have been processed, the article being verified as a legitimate article if all cryptographic links are found between the two or more portions.
In accordance with a fourteenth aspect of the invention, there is disclosed a method of verifying the legitimacy of an article against forgery. The method includes the steps of: extracting at least one invisible watermark from an official seal, the official seal being a securely controlled item of an authority; and comparing the extracted watermark with verification information to determined if the extracted watermark matches the verification information indicating that the article is legitimate.
Preferably, the verification information is information identifying the authority.
Preferably, the method includes the step of generating a watermark dependent upon information forming part of the article to provide the verification information. The information forming part of the article can be biometrics data.
Preferably, the method includes the step of decrypting the watermark.
In accordance with a fifteenth aspect of the invention, there is disclosed an apparatus for verifying the legitimacy of an article against forgery. The apparatus includes: a device for extracting at least one invisible watermark from an official seal, the official seal being a securely controlled item of an authority; and a device for comparing the extracted watermark with verification information to determined if the extracted watermark matches the verification information indicating that the article is legitimate.
In accordance with a sixteenth aspect of the invention, there is disclosed a computer program product having a computer readable medium having a computer program recorded therein for verifying the legitimacy of an article against forgery. The computer program product includes: a module for extracting at least one invisible watermark from an official seal, the official seal being a securely controlled item of an authority; and a module for comparing the extracted watermark with verification information to determined if the extracted watermark matches the verification information indicating that the article is legitimate.